Sanitary absorbent article

ABSTRACT

A sanitary napkin including a central absorbent pad, the central absorbent pad having a liquid pervious cover layer, a liquid impervious barrier layer and an absorbent core between the cover layer and barrier layer. The central absorbent pad includes a pair of flaps adapted to fold over a crotch portion of an undergarment in use. The central absorbent pad further includes two preferential bending axes, each axis being inward from and adjacent to a respective longitudinal side edge and extending obliquely with respect to the longitudinal centerline, the axes converging towards the longitudinal centerline in the first distal end of the central absorbent pad. The preferential bending axes are adapted to enable the sanitary napkin to be folded from an initial substantially hourglass shape to a tapered shape.

FIELD OF THE INVENTION

The present invention relates to disposable absorbent articles, such assanitary napkins with side flaps and two preferential bending axes, eachaxis being inward from and adjacent to a respective longitudinal sideedge and extending obliquely with respect to the longitudinalcenterline, the axes converging towards the longitudinal centerline inthe first distal end of the central absorbent pad.

BACKGROUND OF THE INVENTION

Sanitary napkins having side flaps are disclosed in the literature andare generally available in the marketplace. Generally, the flaps extendlaterally from the side edges of a central absorbent structure and areintended to drape over the edges of the wearer's panties in the crotchregion. Thus, the flaps are disposed between the edges of the wearerspanties in the crotch region and the wearer's thighs. Commonly, theflaps are provided with an attachment means for affixing the flaps tothe underside of the wearer's panties.

The flaps serve at least two purposes. First, the flaps prevent exudatesfrom soiling the edges of the wearer's panties and second, the flaps,when affixed to the underside of the panties, help stabilize the napkinin the undergarment and prevent it shifting out of place.

Sanitary napkins having flaps are disclosed in U.S. Pat. No. 4,687,478,entitled “Shaped Sanitary Napkin With Flaps”, to Van Tilburg on Aug. 18,1987, U.S. Pat. No. 4,608,047, entitled “Sanitary Napkin AttachmentMeans”, to Mattingly on Aug. 26, 1986, U.S. Pat. No. 4,589,876, entitled“Sanitary Napkin”, to Van Tilburg on May 20, 1986, U.S. Pat. No.4,285,343, entitled “Sanitary Napkin”, to McNair on Aug. 25, 1981, U.S.Pat. No. 3,397,697, entitled “Disposable Sanitary Shield ForUndergarments”, to Rickard on Aug. 20, 1968, U.S. Pat. No. 2,787,271,entitled “Sanitary Napkin”, to Clark on Apr. 2, 1957 and U.S. Pat. No.4,900,320, entitled “Sanitary Napkin With Undergarment Gathering Flaps,to McCoy on Feb. 13, 1990, all of which are incorporated herein byreference in their entirety.

While sanitary napkins having flaps are commonly viewed as providingbetter protection against soiling as compared to sanitary napkinswithout flaps, these napkins commonly experience a problem that keepsthem from being optimally effective.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sanitary napkinhaving flaps that is adaptable for use in a variety of styles of women'sundergarments, including briefs, bikinis, thongs, and the like.

In accordance with the present invention, there has been provided asanitary napkin that is adapted to be worn in a user's undergarment. Thesanitary napkin comprises a central absorbent pad, the central absorbentpad having a liquid pervious cover layer, a liquid impervious barrierlayer and an absorbent core between the cover layer and barrier layer, alongitudinal centerline, a lateral centerline, a pair of oppositelongitudinal side edges, a first distal end and an opposite seconddistal and a flap extending laterally outward from each longitudinalside edge along a line of juncture, each flap being substantiallyadjacent the lateral centerline and adapted to fold over a crotchportion of an undergarment in use, the central absorbent pad furthercomprising two preferential bending axes, each axis being inward fromand adjacent to a respective longitudinal side edge and extendingobliquely with respect to the longitudinal centerline, the axesconverging towards the longitudinal centerline in the first distal endof the central absorbent pad.

These and other objects of the present invention will be more readilyapparent when considered in reference to the following description andwhen taken in conjunction with the accompanying drawings. It is to beunderstood, however, that the drawings are provided for purposes ofillustration only and not as a definition of the boundaries of theinvention, for which reference should be made to the appending claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a sanitary napkin according to the presentinvention;

FIG. 2 is a side cut away view of the sanitary napkin of FIG. 1 takenthrough lines 2-2;

FIG. 3 is a bottom plan view of a sanitary napkin according to thepresent invention.

DETAILED DESCRIPTION

The present invention relates to sanitary napkins adapted to be worn ina crotch portion of a wearer's undergarment in use. The napkin comprisesa central absorbent pad having a liquid pervious cover layer, a liquidimpervious barrier layer and an absorbent core between the cover layerand barrier layer. The central absorbent pad 12 will generally have anabsorbent capacity sufficient to absorb the anticipated total amount ofmenstrual fluid. Central absorbent pad 12, is preferably thin, i.e. lessthan about 5 mm in caliper. It has been found that a sanitary napkinhaving a narrow, thin absorbent core is extremely comfortable to theuser.

The central absorbent pad has a longitudinal centerline, a lateralcenterline, a pair of opposite longitudinal side edges, a first distalend, an opposite second distal and a central region intermediate thefirst distal end and the second distal end. The napkin is provided withside flaps that are adapted to be folded over the edges of a crotchportion of the wearer's undergarment in use. Each flap extends laterallyoutward from each longitudinal side edge along a line of juncture. Thecentral absorbent pad further comprises two preferential bending axes,each axis being inward from and adjacent to a respective longitudinalside edge from at least the central region of the central absorbent padto the first distal end. The preferential bending axes extend obliquelywith respect to the longitudinal centerline and converge towards thelongitudinal centerline as they extend from the central region to thefirst distal end of the central absorbent pad.

As used herein, the term “sanitary napkin” refers to an article which isworn by females in an undergarment adjacent to the pudendal region andwhich is intended to absorb and contain the various exudates which aredischarged from the body (e.g., blood menses, and urine) and which isintended to be discarded after a single use (i.e., it is not intended tobe laundered or otherwise restored or reused).

A specific example of implementation of a sanitary napkin according tothe present invention is illustrated in FIG. 1. The sanitary napkindesignated by the reference numeral 10 basically comprises a main bodyrepresented by central absorbent pad 12. The central absorbent pad 12has an imaginary longitudinal centerline 80, an imaginary lateralcenterline 85, a pair of opposite longitudinal side edges 90, 90′, afirst distal end 93 and an opposite second distal end 95 and a centralregion 94, intermediate the distal ends. Topsheet 14 and backsheet 18are joined at seam 39 (also commonly referred to as a flange seal)around the entire periphery of sanitary napkin 10. The purpose of thisseam is to unite the various elements of the sanitary napkin into aunitary structure. Seam 39 can be formed by any means commonly used inthe art for this purpose such as by gluing, crimping, or heat-sealing.Seam 39 is illustrated extending completely around the periphery ofsanitary napkin 10; this is suitable for ease of construction. However,other means of uniting the various elements can be used. As shown inFIG. 2, central absorbent pad 12 comprises absorbent core 16, topsheet14 and backsheet 18, wherein backsheet 18 is disposed on a side ofabsorbent core 16 that is opposite that of topsheet 14.

Topsheet 14 is liquid permeable and, when sanitary napkin 10 is in use,is in close proximity to the skin of the user. Topsheet 14 is compliant,soft feeling, and non-irritating to the user's skin. It can be made fromany of the materials conventional for this type of use. Non-limitingexamples of suitable materials that can be used as topsheet 14 are wovenand nonwoven fabrics formed from polyester, polypropylene, nylon, and/orrayon fibers or the topsheet may be an apertured thermo-plastic film.Apertured formed films are preferred for topsheet 14 because they arepervious to liquids and yet non-absorbent. Thus, the surface of theformed film that is in contact with the body remains dry and is morecomfortable to the wearer.

Backsheet 18 is impervious to liquids and, thus, prevents menstrualfluid from soiling the clothing of the user. Any material used in theart for such purpose can be utilized herein. Suitable materials includeembossed or non embossed polyethylene films and laminated tissue.

Absorbent core 16 provides the means for absorbing menstrual fluid.Absorbent core 16 is generally compressible, comfortable andnon-irritating to the user's skin. It can comprise any material used inthe art for such purpose. Examples include comminuted wood pulp that isgenerally referred to as airfelt, creped cellulose wadding, absorbentfoams, absorbent sponges, absorbent hydrogel materials, polymericfibers, or any equivalent material or combinations of materials. In apreferred embodiment, as shown in FIGS. 1 and 3, the absorbent core 16is wider in the second distal end 95 and tapers continuously towards thefirst distal end 93. By tapering the absorbent core 16 yet maintainingsubstantially the same width of the other components in the centralabsorbent pad 12, a pair of opposite preferential bending axes 30, 30′are formed along the edges of the absorbent core in the region from atleast the central region 94 to the first distal end 93.

In an alternative embodiment (not shown) the longitudinally extendingside edges of the absorbent core extend substantially parallel to andslightly inward from the longitudinal side edges of the centralabsorbent pad. In accordance with this embodiment, the preferentialbending axes may be formed by embossing the absorbent core to formlongitudinally extending channels that are capable of acting as a hinge.

Referring now to FIGS. 2 and 3, the portion of the outer surface ofbacksheet 18 that is generally in vertical registration with absorbentcore 16 is provided with central absorbent pad adhesive 20. Centralabsorbent pad adhesive 20 provides an adhesive attachment means forsecuring central absorbent pad 12 to the crotch portion of aundergarment. Any adhesive or glue used in the art for such purpose canbe used herein, with pressure-sensitive adhesive being preferred.Suitable adhesives are Century A-305IV manufactured by the CenturyAdhesives Corporation and Instant LOK 34-2823 manufactured by NationalStarch Company. The central absorbent pad adhesive may be the same widthas absorbent core, or as shown in FIG. 3 it may be a plurality ofrelatively narrow stripes. However, the width is not critical andappropriate widths, as well as lengths, can be readily selected by thoseskilled in the art. The pressure-sensitive adhesive of central absorbentpad adhesive 20 should be covered with central absorbent pad liner 22 tokeep the adhesive from drying out and to keep it from sticking toextraneous surfaces prior to use. Any commercially available releaseliner commonly used for such purposes can be used herein. Nonlimitingexamples of suitable release liners are BL30MG-A SILOXE1/0 and BL 30MG-A SILOX 4/P/O both of which are manufactured by the AkrosilCorporation.

As can be observed from the foregoing, central absorbent pad 12comprises an absorbent core having an upper surface covered by a fluidpervious body contacting surface (represented in FIG. 2 by topsheet 14)and an opposed liquid impervious surface (represented in FIG. 2 bybacksheet 18). It is to be understood that the embodiment illustrated isonly one possible embodiment. Other possible embodiments include one inwhich an absorbent core is essentially completely wrapped with topsheetbefore it is placed on a backsheet. The absorbent core can also comprisean absorbent layer which possesses sufficient integrity to stand-aloneand which is fluid permeable on one surface while the other surface hasbeen treated to render it liquid impervious.

It should be noted that a relatively narrow central absorbent pad 12 iseffective because the overall configuration and use of sanitary napkin10 results in central absorbent pad 12 being maintained in closeproximity to the body. Such proximity of central absorbent pad 12 placesit precisely where it should be: very near the body at the vaginalopening. Central absorbent pad 12 can then absorb the vast majority ofthe menstrual fluid (menses) before it has an opportunity to flow alongthe central absorbent pad 12. As shown in FIG. 1, the absorbent core 16is generally tapered from a relatively wide distal end region to arelatively narrow opposite distal end region so as to conform generallyto the wearer's thighs and to be easily conformable to a variety ofundergarment styles. The width of the wider second distal end ispreferably less than 75 mm, more preferably from about 60 mm to 70 mm.Generally, the width of a central portion of the crotch portion of anundergarment is from about 45 mm to about 75 mm. It is preferred thatthe width of the central region 94 of the central absorbent pad 12 isless than or equal to the width of the undergarment in this region. Thewidth of the absorbent core preferably continuously tapers from thesecond distal end toward the first distal end, the first distal endhaving a width of less than 30 mm, preferably about 15 to 20 mm. Whilethe taper is illustrated as being a substantially straight line and suchconstitutes a preferred embodiment, other variations are considered tobe within the scope of the present invention such as curved or arcuatelines. In use, if the wearer chooses an undergarment style such as abrief style, both of the distal end regions of the sanitary napkinremain substantially planar within the undergarment, and thus remain incontact with the wearer's body. However, if the undergarment style is athong or tanga type undergarment, then the sanitary napkin of thepresent invention is adapted to fold along the preferential bendinglines 30, allowing the relatively narrow distal end region of theabsorbent core to remain on a body-facing side of the wearer'sundergarment while the side margins 33, 33′ of the first distal endregion of the central absorbent pad comfortably fold around the edges ofthe undergarment. The side margins should have a lateral dimensionsufficient to enable the side margin to be folded around the edges ofthe undergarment. Accordingly, the side margins have a lateral dimensionas measured from the preferential bending line 30 to the longitudinalside edge 90 in the first distal end that is sufficient to allow theside margin to fold over the edges of a thong style undergarment in use.In general, a lateral dimension of at least 7 mm has been found to besufficient and the lateral dimension is preferably about 10 to 20 mm. Asshown in FIG. 3, it is preferred that the side margins 33, 33′ have anadhesive attachment means 20 on a garment faceable side of the backsheetthat is adapted to allow a wearer to adhesively affix the side marginsto their undergarment in use.

The central absorbent pad 12 has two flaps 24 and 24′ extendinglaterally outward from the longitudinal side edges of the centralabsorbent pad 12 in a central portion thereof adjacent the lateralcenterline. As shown in FIG. 1 flaps 24 and 24′ extend substantiallyalong the lateral centerline 85. As used herein, the terminology“central portion” and “lateral centerline” refer generally to a regionof the central absorbent pad 12 that is intended to be placed in acrotch portion of a wearer's undergarment. Thus, for some embodiments ofthe invention wherein the sanitary napkin is asymmetrical, such as in aproduct intended for overnight use, the central portion and lateralcenterline may not be located in the exact geometric center of thecentral absorbent pad. While it is not necessary that the flaps bemirror images of one another they preferably are. Topsheet 14 forms onesurface of flaps 24, 24′ while backsheet 18 forms the other surface. Ingeneral, the flaps do not require a topsheet to enable them to functionproperly, but the use of a topsheet is preferred. Flap topsheet can beintegral with the central absorbent body, as illustrated, or it can bean independent element; the former being preferred. All of the specificphysical properties of the topsheet 14 previously described, apply toany flap topsheet that is used. There is, however, no requirement thatthe flap topsheet be the same material as the topsheet associated withthe central absorbent pad. In one possible embodiment, the flap topsheetmay be nonwoven material while the topsheet over the central absorbentpad is an apertured polymeric film. In the embodiment illustrated inFIG. 2, backsheet 18 serves as a backsheet for flaps 24 and 24′. Theflaps require a backsheet (or more generally, a liquid imperviousmaterials) to enable them to function properly. The flap backsheet canbe integral with the absorbent core liquid impervious surface or theycan be independent elements. All of the specific physical properties ofthe backsheet 18 previously described apply to the flap backsheet.

At least a portion of the outer, garment faceable surface of flap 24, ina region adjacent distal edge 78, is coated with flap adhesive 36. Flapadhesive 36 is an adhesive attachment means which is used to assist inmaintaining flap 24 in position after it is wrapped around the edge ofthe crotch portion of the undergarment as described below. Any adhesiveused for central absorbent pad adhesive 20 can be used as flap adhesive36. Also, flap adhesive 36 is covered with a removable flap releaseliner 38. Any release liner material used for central absorbent padrelease liner 22 can be used for flap release liner 38. Each flap 24,24′ is associated with central absorbent pad 12 along a line of juncture26. As used herein, the term “line of juncture” refers to any of variouscurved or straight lines. Each flap 24, 24′ has a distal edge 78 that isremote from a proximal edge defined by the line of juncture 26.

It is to be observed that lines of juncture 26 and 26′ are the linesalong which flaps 24 and 24′ are associated with the absorbent core(represented by central absorbent pad 12); as such they represent linesof demarcation between the absorbent core and the flaps. In theembodiment shown in FIGS. 1 and 3, the lines of juncture 26, 26′ arecoincident with the preferential bending lines 30, 30′ in the centralregion 94 of the central absorbent pad 12.

The sanitary napkin shown in FIGS. 1 and 2 has a substantially linearline of juncture 26. The precise shape of flap 24, as well as theoverall shape of the sanitary napkin 10 can be selected by those skilledin the art without undue experimentation. In the embodiment illustratedin FIG. 1, the flaps are symmetrically disposed along the longitudinalaxis of the sanitary napkin.

The sanitary napkin of the present invention, such as the oneillustrated in FIGS. 1-3, is utilized by removing the release liners 22and 38 and 38′ and thereafter placing the sanitary napkin in aundergarment. The center region of central absorbent pad 12 is placed incrotch portion (not shown) of the undergarment with one end of centralabsorbent pad 12 extending towards the front section of the undergarmentand the other end towards the back section and with the backsheet 18 incontact with the inner surface of center crotch portion of theundergarment. Central absorbent pad adhesive 20 maintains centralabsorbent pad 12 in position. The distal portions of flaps 24 and 24′are folded around, respectively, side edges and of the crotch portion ofthe undergarment. Flap adhesive 36 and 36′ secure flaps 24 and 24′ insuch position, thus, flaps 24 and 24′ are each folded over themselveswith a portion of the undergarment.

1. A sanitary napkin comprising: a central absorbent pad, the centralabsorbent pad having a liquid pervious cover layer, a liquid imperviousbarrier layer and an absorbent core between the cover layer and barrierlayer, a longitudinal centerline, a lateral centerline, a pair ofopposite longitudinal side edges, a first distal end and an oppositesecond distal end, a flap extending laterally outward from eachlongitudinal side edge along a line of juncture, each flap extendingsubstantially along the lateral centerline and adapted to fold over acrotch portion of an undergarment in use, said core being continuouslytapered from the second end towards the first end, the barrier and thecover extending beyond the core, the central absorbent pad furthercomprising two preferential bending axes, each preferential bending axisbeing defined by a respective edge of the core, each axis being inwardfrom and adjacent to a respective longitudinal side edge and extendingobliquely with respect to the longitudinal centerline, the axesconverging towards the longitudinal centerline in the first distal endof the central absorbent pad, wherein the central absorbent pad has apair of opposite side margins, each side margin being adjacent arespective preferential bending line and adapted to fold along saidrespective preferential bending line, each side margin being capable ofbeing folded over an edge of a wearer's undergarment in use, and whereinsaid napkin has a first configuration wherein said napkin is structuredand arranged to be used with a brief style undergarment and a secondconfiguration wherein said side margins are in a folded condition suchthat said napkin is structured and arranged to be used with a thongstyle undergarment.
 2. A sanitary absorbent article as defined in claim1, wherein said preferential bending axes extend from the lateralcenterline to the first distal end.
 3. A sanitary absorbent article asdefined in claim 1, wherein said preferential bending axes extend fromthe second distal end to the first distal end.
 4. A sanitary absorbentarticle as defined in claim 1, wherein the first distal end has a widthof less than 30 mm.
 5. A sanitary absorbent article as defined in claim1, wherein the first distal end has a width of about 15 mm to 20 mm. 6.A sanitary absorbent article as defined in claim 1, wherein each sidemargin has an adhesive attachment means on a garment faceable sidethereof that is adapted to allow a wearer to adhesively affix the sidemargins to their undergarment in use.
 7. A sanitary absorbent article asdefined in claim 1, wherein the side margins have a lateral dimension asmeasured from the preferential bending line to the longitudinal sideedge of at least 7 mm.
 8. A sanitary absorbent article as defined inclaim 1, wherein the side margins have a lateral dimension as measuredfrom the preferential bending line to the longitudinal side edge ispreferably about 10 to 20 mm.
 9. A sanitary absorbent article as definedin claim 1, wherein said two preferential bending axes are structuredand arranged to permit at least a portion of said central absorbent padto be folded along a respective one of said preferential bending axes.10. A sanitary absorbent article as defined in claim 9, wherein saidportion of said central absorbent pad folded along said respective oneof said preferential bending axes is structured and arranged to altersaid central absorbent pad from an initial substantially hourglass shapeto a tapered shape.